Patent GB-795341-A (GB)
Title: A writing instrument incorporating automatic number registering and summating mechanism
IPC: B43K29/08
Filed: 1954-10-18
Abstract: 795,341. Calculating-apparatus. ETABLISSEMENTS W.B.C. Oct. 18, 1954 [Oct. 17, 1953], No. 29958/54. Class 106 (1). [Also in Group XV] A writing instrument incorporates mechanism for automatically registering and summating numbers traced out by the device. Digits of the numbers must be written in a special form and the mechanism responds to the up and down strokes of the digit forms. The writing point 4 of the device shown rocks about a pivot 5 on the body part 6, in correspondence to the up and down strokes, and these movements are transmitted by means of a spindle 18 and crank 19 to a lever 20, causing this lever to rock about its pivot 21 towards and away from the axis of a disc 34 mounted at the end of a shaft 9 connected by means of a universal joint 10 to a rearwardly extending tubular shaft 11. A forward extension 16 of the shaft 9 engages a slot in a block 19 adapted also to be moved transversely to and fro by the tracing point 4 but in opposition to the lever 20. In this way relative movement between the lever 20 and disc 34, due to the up and down strokes, is increased. These movements are, however, of constant amplitude. The face of the disc 34 is formed with two systems of cam grooves engaged by the two prongs of a forked member 22 carried by the lever 20. As a result, the disc 34 is rotated by the member 22 and the cam grooves are so designed that the up and down movements of the various digits result in a net rotation of the disc 34 commensurate with the digit values. Reverse rotation of the disc 34 when subtracting is obtained by rocking the member 22 to engage a second pair of prongs with cam grooves on the opposite face of the disc. , The disc 34 is automatically zeroized when pressure on the point 4 is relaxed after each digit is traced. The body part 6 is adapted to slide inwardly of the main casing against a spring 33 connected to a rod 28 attached to the part 6. When pressure is relaxed, a sleeve 29 on the shaft 9 is moved by the rod 28 to engage its cam end 31 with a pin 32 on the shaft, so turning back the shaft and disc 34 to zero. At the same time, a cone 30 enters a ring 39 which re-centralizes the shaft and disc. A set of internally toothed numeral drums or rings 44 are rotatably mounted within the casing. A corresponding number of rollers 47, each with a pair of diametrically opposed teeth 49, are mounted on the shaft extension 11 and normally beyond the drums 44 with their teeth located in longitudinal slots separating two semi-cylindrical members 42, 43 carried on guides 14 secured to the end of the shaft extension 11. When a digit is registered by the disc 34, the assembly 9, 11, 14, 42 and 43, together with the rollers 47, follows the rotation of disc 34. When pressure on the point 4 is relaxed the rod 28, through a connection 50 and ratchet mechanism 51, 53, causes the assembly of rollers to be stepped forward and to enter the foremost into the adjacent numeral drum 44, this foremost roller 47 registering the digit whilst the others remain within the cylinder 42, 43 and are restored with the disc 34. Further rollers 47 registering subsequent digits are similarly entered into the numeral drums. When all the digits of a number have been traced, the cylinder 42, 43 is moved inwardly of the numeral drums so that cam ends 421 zeroize the rollers 49 and transfer their settings to the drums. Transfer mechanism interconnects the drums, so that successive numbers are added to or subtracted from the total registered.